CutMeshByLevelSetGenerator

This CutMeshByLevelSetGenerator object is designed to trim the input mesh by removing all the elements on outside the give level set with special processing on the elements crossed by the cutting surface to ensure a smooth cross-section. The output mesh only consists of TET4 elements.

Overview

The CutMeshByLevelSetGenerator is an extended version of CutMeshByPlaneGenerator. It is used to trim a 3D input mesh based on a given level set f(x,y,z)=0. The portion of the input mesh that is within the level set (i.e., f(x,y,z)<=0) is retained, while the portion of the input mesh that is outside the level set (i.e., f(x,y,z)>0) is discarded. The input mesh, given by "input", must be 3D and contain only first-order elements. The level set is specified by "level_set", which can be interpreted by FParser as a function of x, y, and z (i.e., f(x,y,z)). As each element that is across the cutting level set is cut based on the interception points, this mesh generator ensures a smooth cut instead of a "zigzag" cut along element boundaries.

Using this mesh generator, a 3D structured mesh defined by a bounding box (e.g., generated by GeneratedMeshGenerator) can be subtracted into a 3D mesh with its shape define by a given level set.

Methods

CutMeshByLevelSetGenerator first converts all elements of the input mesh into TET4 elements. Next, the TET4 elements sliced by the level set are further split into TET4 elements. This mesh generator uses exact the same algorithm as its sibling mesh generator, CutMeshByPlaneGenerator. At the first-order element level, cutting by a plane and cutting by a level set are the same.

Example Syntax

[Mesh]
  [lsc]
    type = CutMeshByLevelSetGenerator
    input = block_1
    level_set = 'x*x+y*y+z*z-0.81'
    cut_face_id = 345
    cut_face_name = ls
  []
[]

Input Parameters

inputThe input mesh that needs to be trimmed.
C++ Type:MeshGeneratorName
Controllable:No
Description:The input mesh that needs to be trimmed.
level_setLevel set used to cut the mesh as a function of x, y, and z.
C++ Type:std::string
Controllable:No
Description:Level set used to cut the mesh as a function of x, y, and z.

Required Parameters

constant_expressionsVector of values for the constants in constant_names (can be an FParser expression)
C++ Type:std::vector<std::string>
Controllable:No
Description:Vector of values for the constants in constant_names (can be an FParser expression)
constant_namesVector of constants used in the parsed function
C++ Type:std::vector<std::string>
Controllable:No
Description:Vector of constants used in the parsed function
cut_face_idThe boundary id of the face generated by the cut. An id will be automatically assigned if not provided.
C++ Type:short
Controllable:No
Description:The boundary id of the face generated by the cut. An id will be automatically assigned if not provided.
cut_face_nameThe boundary name of the face generated by the cut.
C++ Type:BoundaryName
Controllable:No
Description:The boundary name of the face generated by the cut.
epsilon1e-12Fuzzy comparison tolerance
Default:1e-12
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Fuzzy comparison tolerance

Optional Parameters

disable_fpoptimizerFalseDisable the function parser algebraic optimizer
Default:False
C++ Type:bool
Controllable:No
Description:Disable the function parser algebraic optimizer
enable_ad_cacheTrueEnable caching of function derivatives for faster startup time
Default:True
C++ Type:bool
Controllable:No
Description:Enable caching of function derivatives for faster startup time
enable_auto_optimizeTrueEnable automatic immediate optimization of derivatives
Default:True
C++ Type:bool
Controllable:No
Description:Enable automatic immediate optimization of derivatives
enable_jitTrueEnable just-in-time compilation of function expressions for faster evaluation
Default:True
C++ Type:bool
Controllable:No
Description:Enable just-in-time compilation of function expressions for faster evaluation
evalerror_behaviornanWhat to do if evaluation error occurs. Options are to pass a nan, pass a nan with a warning, throw a error, or throw an exception
Default:nan
C++ Type:MooseEnum
Options:nan, nan_warning, error, exception
Controllable:No
Description:What to do if evaluation error occurs. Options are to pass a nan, pass a nan with a warning, throw a error, or throw an exception

Parsed Expression Advanced Parameters

enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:No
Description:Set the enabled status of the MooseObject.
save_with_nameKeep the mesh from this mesh generator in memory with the name specified
C++ Type:std::string
Controllable:No
Description:Keep the mesh from this mesh generator in memory with the name specified

Advanced Parameters

nemesisFalseWhether or not to output the mesh file in the nemesisformat (only if output = true)
Default:False
C++ Type:bool
Controllable:No
Description:Whether or not to output the mesh file in the nemesisformat (only if output = true)
outputFalseWhether or not to output the mesh file after generating the mesh
Default:False
C++ Type:bool
Controllable:No
Description:Whether or not to output the mesh file after generating the mesh
show_infoFalseWhether or not to show mesh info after generating the mesh (bounding box, element types, sidesets, nodesets, subdomains, etc)
Default:False
C++ Type:bool
Controllable:No
Description:Whether or not to show mesh info after generating the mesh (bounding box, element types, sidesets, nodesets, subdomains, etc)

Debugging Parameters

(moose/test/tests/meshgenerators/cut_mesh_by_level_set_generator/simple_cut.i)

[Mesh]
  [gmg]
    type = GeneratedMeshGenerator
    dim = 3
    nx = 4
    ny = 4
    nz = 4
    xmin = -1
    ymin = -1
    zmin = -1
    elem_type = HEX8
  []
  [block_1]
    type = ParsedSubdomainMeshGenerator
    input = gmg
    combinatorial_geometry = 'z>0'
    block_id = 1
  []
  [lsc]
    type = CutMeshByLevelSetGenerator
    input = block_1
    level_set = 'x*x+y*y+z*z-0.81'
    cut_face_id = 345
    cut_face_name =ls
  []
[]

Overview
Methods
Example Syntax
Input Parameters